Absorbent articles such as disposable diapers are provided with fastener portions which are adhered to the body of the absorbent article through one of its end portions, the so-called manufacturer's end, by means of, for example, an adhesive layer. The opposite end portion of the fastener portion which is usually referred to as user's end, comprises a fastening means such as an adhesive fastening means or a mechanical fastening means to close the absorbent article around the wearer's body and fasten the absorbent article on the body. FIGS. 1a and b show a disposable diaper of the state of the art having an hour-glass shape in an open (FIG. 1a) and in a closed form (FIG. 1b), respectively. It can be seen from FIG. 1b that the diaper comprises an absorbent core 4 between a back sheet 3 and a top sheet 2. The manufacturer's end 11 of the fastener portion 10 is adhered to the side panel 6 of the diaper and the user's end 12 is fastened to the landing zone 5 on the front. waistband portion 7b on the back sheet 3 of the diaper.
EP 0,379,850 discloses a method for manufacturing fastener portions having rounded grip-ends or fingerlifts in order to avoid that the wearer of the diaper is hurt or even cut by sharp-edged fingerlifts. A pair of fastener portions is die-cut continuously from a web of fastener portions, and the fastener portions obtained are applied continuously to the edge portions of two different diapers conveyed side-by-side on a conveyor belt. Other methods for forming a plurality of fastener portions, which can be integrated into continuous manufacturing lines for diapers, are disclosed, for example, in WO 98/03,140, U.S. Pat. No. 5,399,219 and U.S. Pat. No. 5,876,531.
WO 84/04,242 discloses another diaper shape wherein the side panels 6 of the diaper are not integrated into the body portion of the diaper so that such body portion is essentially rectangular. A similar construction is shown, for example, in U.S. Pat. No. 5,527,302. In these constructions, the dimensions of the fastener portions 10 are typically larger than the dimensions of fastener portions used in conjunction with diapers comprising side panels 6 integrated into the body portion of the diaper like those shown in FIGS. 1a and b. The larger dimension of the fastener portions 10 is required in order to provide a reliable and stress-free fit of the diaper comprising no integrated side panels 6, on the wearer. Strip-type fastener portions used in conjunction with integrated side panels 6 like those shown by referral number 10 in FIGS. 1a and b, are often referred to as fastener tapes whereas fastener portions like those disclosed in U.S. Pat. No. 5,527,302 are often referred to as big ear fastener portions.
Fastener portions often comprise in addition to the fastening means an elastic means in order to impart stretchability to the fastener portions. Stretchable fastener portions are disclosed, for example, in U.S. Pat. No. 5,527,302 and in WO 99/03,347.
While fastener portions comprising an elastic means are generally advantageous and tend to improve the fit of the diaper to the wearer, they may exhibit a reduced stiffness in comparison to fastener portions comprising no elastic means. This may adversely affect the handleability of fastener portions comprising an elastic means and render the attachment of such fastener portions to the body portion of a diaper difficult, in particular, under high speed manufacturing operations.
It has also been difficult in prior art to provide a method for applying a fastener portion to a diaper so that the fastener portion is easy to open and is also resistant to undesired, premature opening. EP 0,321,232 discloses, for example, a fastener portion comprising both an adhesive and a mechanical fastening means. The fastener portion is attached to the diaper through its manufacturer's end and then folded over onto the inner surface of the top sheet of the diaper where the adhesive means adheres to the inner surface of the top sheet thereby preventing premature “pop open” (“flagging”) of the fastener portion while the absorbent article is still being processed on the diaper line, for example. Flagging of fastener portions may result in disrupturing fastener portions in subsequent processing steps and/or adversely affect the folding of the diaper into a packagable state.
It was therefore an object of the present invention to provide an improved method of applying a fastener portion to absorbent articles which can be effectively applied under high speed manufacturing conditions and/or which does not exhibit the shortcomings of the prior art or exhibit them to a lower degree only.
It was another object of the present invention to provide a fastener portion which when applied to an absorbent article, does not “pop open” prematurely.
Other object of the present invention can be taken from the following detailed description of the invention.